Active night vision system for vehicles employing short-pulse laser illumination and a gated camera for image capture
First Claim
1. A method of detecting objects with a night vision system having a near infrared light source and a camera, the method comprising:
- activating said light source in the form of a sequence of light pulses wherein each light pulse is increasing in intensity for a predetermined number of pulses to form a pulse train; and
activating said camera in the form of a corresponding sequence of non-overlapping detection windows wherein each of said windows corresponds to one of said light pulses for receiving reflected light resulting from said corresponding light pulse and a time delay between each corresponding light pulse and detection window is increasing throughout said pulse train, said light pulse intensity and said corresponding time delay being selected to result in a substantially constant reflected image signal.
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Abstract
A method of detecting objects with a night vision system is provided. The night vision system includes a light source and a camera. The method includes activating the light source as a sequence of light pulses wherein each light pulse is increasing in intensity for a predetermined number of pulses to form a pulse train. The camera is activated as a corresponding sequence of detection windows wherein each of the windows corresponds to one of the light pulses for receiving reflected light resulting from the corresponding light pulse. The light pulses and detection windows are configured such that a time delay between each corresponding light pulse and detection window is increasing throughout the pulse train. In another variation, the camera gain is increased throughout the pulse train. In yet another variation, the light pulses have constant amplitude, the camera gain is constant for all pulses, and the number of camera gain windows increases as the delay increases. In all cases, objects nearer the night vision system are imaged with lower intensity light, less camera gain, and/or fewer laser pulses than objects further away to provide a composite image in which the apparent brightness of near and far objects can be controlled.
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Citations
19 Claims
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1. A method of detecting objects with a night vision system having a near infrared light source and a camera, the method comprising:
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activating said light source in the form of a sequence of light pulses wherein each light pulse is increasing in intensity for a predetermined number of pulses to form a pulse train; and
activating said camera in the form of a corresponding sequence of non-overlapping detection windows wherein each of said windows corresponds to one of said light pulses for receiving reflected light resulting from said corresponding light pulse and a time delay between each corresponding light pulse and detection window is increasing throughout said pulse train, said light pulse intensity and said corresponding time delay being selected to result in a substantially constant reflected image signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method of detecting objects with a night vision system having a near infrared light source and a camera, the method comprising:
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activating said light source in the form of a sequence of constant intensity light pulses to form a pulse train; and
activating said camera in the form of a corresponding sequence of non-overlapping detection windows wherein each of said windows corresponds to one of said light pulses for receiving reflected light resulting from said corresponding light pulse and wherein each detection window has an increasing gain throughout said pulse train and a time delay between each corresponding light pulse and detection window is increasing throughout said pulse train, said detection window gain and said corresponding time delay being selected to result in a substantially constant reflected image signal. - View Dependent Claims (11, 12, 13, 14, 15, 16)
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17. A method of detecting objects with a night vision system having a near infrared light source and a camera, the method comprising:
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activating said light source in the form of a plurality of constant intensity light pulses to form a pulse train; and
activating said camera in the form of a plurality of non-overlapping detection windows throughout said pulse train for receiving reflected light resulting from said corresponding light pulses and wherein a time delay between each subsequent detection window and a window length is increasing throughout said pulse train, said light pulses and detection windows being configured such that objects nearer the night vision system are imaged by fewer light pulses than objects further away from said night vision system. - View Dependent Claims (18, 19)
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Specification